This page contains information on updating the Eclipse SDK branding elements (icon, splash screen, etc).
The splash screen used for both the Eclipse SDK and Eclipse Platform Runtime is located in the bundle org.eclipse.platform (see in Git repository). It is a single file called splash.bmp (a 452x302 bitmap). The same directory in the source tree contains some PhotoShop source files that can be used to update the splash. Typically each year the splash needs updating with the current year in the copyright statement, and the name of the Simultaneous Release.